Inkjet printing apparatus and inkjet printing method

Abstract

A mask of Y for a first pass is a mask in which a checker pattern having a high frequency characteristic is made to be the arrangement of the print permitting pixels, and a mask of C for the first pass is a mask in which a random image having a lower frequency characteristic is made to be the arrangement of the print permitting pixels. Further, each of the masks of Y and C for a second pass has an arrangement that mutually complements the arrangement of the print permitting pixels of the mask for the first pass. By using such masks, unevenness of the permeation speed caused by beading on a printing medium can be reduced. Further, high tolerance for interference to the mask of the prior pass and for influence of external disturbances can be achieved.

1. An ink jet printing apparatus comprising:
 a printing head including a first and second nozzle arrays, each of which is provided with a plurality of nozzles for ejecting ink for printing on a printing medium; 
 a scanning unit for performing relative scanning of the print head and the printing medium in a direction intersecting an arrangement direction of nozzles in the nozzle arrays over a same area of the printing medium a plurality of times; and 
 a dividing unit configured to divide print data for each nozzle array into print data for each of the plurality of times of scanning, according to a dot arrangement pattern of dots for determining an arrangement of dots in the area for dividing the print data, 
 wherein the dot arrangement pattern corresponding to the first nozzle array ejects ink earlier than the second nozzle array to the area has a higher frequency characteristic than that of the dot arrangement pattern corresponding to the second nozzle array array. 
 
     
     
       2. The ink jet printing apparatus as claimed in  claim 1 , wherein said dividing unit uses a mask as the dot arrangement pattern determined corresponding to the nozzle array. 
     
     
       3. The ink jet printing apparatus as claimed in  claim 1 , wherein the dot arrangement pattern corresponding to the first nozzle array ejecting ink earlier than the second nozzle array to the area in the same scanning has a higher frequency characteristic than that of the dot arrangement pattern corresponding to the second nozzle array. 
     
     
       4. The ink jet printing apparatus as claimed in  claim 1 , wherein the dot arrangement pattern corresponding to the first nozzle array ejecting ink in a first scanning of the plurality of times of the scanning to the area has a higher frequency characteristic than that of the dot arrangement pattern corresponding to the second nozzle array in the first scanning of the plurality times of the scanning to the area. 
     
     
       5. A data generating apparatus that generates print data used in an ink jet printing apparatus that performs relative scanning of a printing medium and a printing head including first and second nozzle arrays, each of which is provided with a plurality of nozzles for ejecting ink for printing on the printing medium, in a direction intersecting an arrangement direction of nozzles in the nozzle arrays over a same area of the printing medium a plurality of times, said data generating apparatus comprising:
 a dividing unit configured to divide print data for each nozzle array into print data for each of the plurality of times of scanning, according to a dot arrangement pattern of dots for determining an arrangement of dots in the area for dividing the print data, 
 wherein the dot arrangement pattern corresponding to the first nozzle array ejecting ink earlier than the second nozzle array to the area has a higher frequency characteristic than that of the dot arrangement pattern corresponding to the second nozzle array. 
 
     
     
       6. A program for causing a computer to function as the data generating apparatus as claimed in  claim 5 . 
     
     
       7. An ink jet printing method of performing relative scanning of a printing medium and a printing head including a first and second nozzle arrays, each of which is provided with a plurality of nozzles for ejecting ink for printing on the printing medium, in a direction intersecting an arrangement direction of nozzles in the nozzle arrays over a same area of the printing medium a plurality of times, said method comprising:
 a dividing step of dividing print data for each nozzle array into print data for each of the plurality of times of scanning, according to a dot arrangement pattern of dots for determining an arrangement of dots in the area for dividing the print data, 
 wherein the dot arrangement pattern corresponding to the first nozzle array ejecting ink earlier than the second nozzle array to the area has a higher frequency characteristic than that of the dot arrangement pattern corresponding to the second nozzle array.